noun

regalia

rih-GAY-lee-uh/rɪˈɡeɪliə/

Distinctive clothing and accessories associated with a rank, ceremony, or activity.

The royal regalia include a crimson robe, crown, and scepter.

A neatly arranged set of ceremonial royal regalia: an ermine-trimmed crimson robe, a gold crown, and a ceremonial scepter, displayed together without a wearer.

Etymology

The king-related pieces formed Latin ‘royal things.’ The modern sense probably developed through royal emblems such as crowns and scepters, extending to ceremonial clothing and insignia of other ranks or orders.

In context

SOAS University of London33:34

it shows the king bedecked in royal regalia and gems which sparkle thanks to these wispy lines of white that shoot off from every diamond and pearl

ReSIA – Natasha Morris – The King and I: Qajar Portrait Miniatures

More examples

Graduates wear academic regalia as they cross the stage.
The dancers wear traditional regalia for the ceremony.
He arrives in full fishing regalia, including a vest and waders.

Forms

regalia

regal adjective — Relating to royalty or suggesting royal splendor.

Similar words

attire: Clothing generally, without necessarily suggesting rank or ceremony.
finery: Elegant or elaborate clothing, not necessarily associated with official status.
insignia: Badges or symbols of rank rather than the complete outfit.